Proposal (236) to South American Classification Committee

 

Change linear sequence of Henicorhina species

 

Proposal: Henicorhina species currently recognised by SACC are listed in the following sequence:

 

Henicorhina leucosticta White-breasted Wood-Wren

Henicorhina leucophrys Gray-breasted Wood-Wren 

Henicorhina negreti Munchique Wood-Wren

Henicorhina leucoptera Bar-winged Wood-Wren

 

Henicorhina includes two widespread and well-known species groups: lowland H. leucosticta and highland H. leucophrys.  Henicorhina leucoptera and H. negreti are each (relatively) recently described (Fitzpatrick et al. 1977; Salaman et al. 2003) and both were thought related to H. leucophrys taxa at the time of their description.

 

A recent molecular (mtDNA) phylogeny published by Dingle et al. (2006) did not include samples of H. negreti but held H. leucoptera to be more closely related to H. leucosticta inornata than H. leucophrys. This would mandate a change in the SACC's linear sequence to move leucoptera next to leucosticta. In Salaman et al. (2003), we presented morphological and biogeographical evidence supporting the hypothesis that H. negreti is more closely related to nominate H. leucophrys than any other taxon. This species should therefore stay where it is in the absence of evidence of closer relationships to other taxa.

 

Moving leucoptera up, as proposed, produces the following linear sequence:

 

Henicorhina leucosticta White-breasted Wood-Wren

Henicorhina leucoptera Bar-winged Wood-Wren

Henicorhina leucophrys Gray-breasted Wood-Wren 

Henicorhina negreti Munchique Wood-Wren

 

Discussion: Dingle et al. (2006) and Mann et al. (2006)'s phylogenies are each consistent with two well-supported sister clades existing in Henicorhina (i) for H. leucosticta taxa (which Dingle et al. show to include H. leucoptera); and (ii) for H. leucophrys taxa (which would presumably include H. negreti). Following a ruling on Proposal 219, Mann et al. (2006)'s phylogeny may mandate a change in the sequence of the genera Thryothorus, Henicorhina and Cyphorhinus. However, even if such steps were taken, this would not require any up-ending of this proposed sequence for Henicorhina. The proposed sequence above would minimise change within the genus Henicorhina whether the genus was placed before or after Thryothorus or Cyphorhinus - it "makes sense" in the context of the Dingle et al. phylogeny reading top to bottom or bottom to top.

 

There are likely to be various splits to current Henicorhina species in the future. Dingle et al. (2006) suggested splitting H. leucosticta into at least three taxa: (i) a Central American prostheleuca group; (ii) a Chocó inornata group; and (iii) an Amazonian leucosticta group. Such propositions lack published vocal or morphological analysis in support and material in northwestern Colombia where the inornata and prostheleuca groups come closest together was not sequenced. However, Dingle et al.'s proposed splits nonetheless appear to have very strong molecular support. Winker et al. (1996) further suggested that some taxa in Dingle et al.'s prostheleuca group could also be split (and the race dariensis, presumably part of this group, ranges into northern Colombia thus is SACC relevant). Finally, in Salaman et al. (2003), evidence was presented that H. leucophrys (as currently constituted) may require to be split in the long term due to parapatry or sympatry of various vocally and morphologically distinctive forms in Colombia apparently without hybridisation (e.g. brunneiceps / nominate leucophrys in the West Andes and bangsi/anachoreta in Santa Marta. Dingle et al. (2006) also demonstrated that various distinct lineages exist within H. leucophrys. The linear re-arrangement in this proposal is therefore just a preliminary step towards a better arrangement for Henicorhina. If Dingle et al. (2006)'s splits were followed, the taxa H. prostheleuca and H. inornata would need inserting after H. leucosticta but with no disruption necessary to the new sequence above.

 

Conclusion: To confirm, this proposal is just to change the linear sequence (move H. leucoptera to above H. leucophrys), not for any of the splits discussed above. I would recommend a YES vote.

 

References are all on SACC references site.

 

Thomas Donegan, August 2006.

 

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Comments from Stiles: "YES. The proposal seems logical, reasonably noncontroversial and involving only a minor change in the list in any case, so YES."

 

Comments from Jaramillo: "YES - Appears to be a well supported and sensible small change."

 

Comments from Pacheco: "YES. A alteraćčo sugerida na sequźncia é muito bem corroborada."